Several microcontact structures for partly implanted neuroprostheses are known whose spatial microcontact arrangement is fixed by a rigid, preshaped area (see for example in U.S. Pat. No. 5,215,088).
Several microcontact structures for partially implanted neuroprostheses are known whose spatial microcontact arrangement is fixed by a partly elastic, flexible, preshaped area and that can alter as a result of the type of implant attachment and also as a result of passive matching to the tissue shape in the implant area (see for example DE-A-4424753).
The production of such a microcontact structure is disclosed (for example) in “Flexible, polyimide-based neural interfaces” Stieglitz et al, J-U. Proceedings of the Seventh International Conference on Microelectronics for Neural, Fuzzy and Bio-Inspired Systems and in IEEE Comput. Soc. 1999, pp. 112–19. Los Alamitos, Calif., USA.
A disadvantage of the known microcontact structures is that no devices and methods are provided for explantation of the microcontact structure.
Furthermore, known microcontact structures do not have mechanisms that carry out matching of the microcontact structure to the shape of the tissue to be contacted. It is therefore not possible to minimise the spacing between the microelectrodes and the neurones to be stimulated in the nerve tissue.
A further disadvantage of known microcontact structures is that they do not have the possibility of spontaneous attachment of the microcontact structure to the nerve tissue.
A disadvantage of the currently designed or available microcontact structures for epiretinal optic prostheses is that they lack features that permit incorporation in the eye in spatially compressed shape and complicated surgical techniques are therefore necessary. This difficulty will heighten in the future as the spatial dimensions of the microcontact structures become greater with an increasing number of contacts.
Furthermore, the available microcontact structures for epiretinal optic prostheses are incapable of covering the neurones of the retina that connect the region of sharpest vision with a high microcontact density since such neurones are situated in so-called parafoveal cell craters that are distinguished by a spatial crater structure.